Wyeth has a strong pipeline, pays a decent dividend and doesn't have big patent problems. So, why is its stock trading at such a big discount?

BIG PHARMA IS GETTING a second look from investors seeking havens from rising interest rates, oil prices and inflation.

But not all large U.S drug stocks are so safe. Patent expirations could rob the industry of $20 billion in sales over the next three years. Pfizer is fending off threats to its cholesterol drug Lipitor's patent. Meanwhile,...